Напольная акустика — Castle Knight 4

The Knight 4 is a floorstanding speaker belonging to the Knight Series of Castle, the British loudspeaker brand. The Knight family counts five models finished in real-wood veneers, and Castle introduced it in the owner manual as its new entry level range, one where the veneered cabinets are still hand built and craftsman finished while value-engineered components and simplified building techniques keep the price in check.

Key specs that matter

Two 130mm bass drivers share the cabinet with a 25mm tweeter, and the crossover point is 3 kHz. Castle gives a frequency range of 36Hz to 24kHz, sensitivity of 90 dB at 1W and 1m and a nominal load of 8 ohms, with a recommended amplifier power of 25 to 150W. The enclosure is 840mm tall, 165mm wide and 270mm deep and weighs 12.5 kg per speaker. The bass loading is tuned to a resonance of 45Hz. Buyers can choose among five veneers - Cherry, Walnut, Mahogany, Black Oak and Antique Oak - all selected from deep figured wood and coated with semi matt clear lacquer.

Engineering and use context

The operating mode is Quarter Wave, and the function is 2 channel stereo. Bass loading follows Castle's quarter wavelength principle, described in the manual as a particular type of transmission line. The company says this approach extends low frequencies smoothly and avoids the upper bass hot zones found in many ported enclosures. The line terminates at a vent below the speaker, where its output is added to the direct radiation of the drivers. A plinth fixed with four round head screws is part of the acoustic design, and spacing washers hold the cabinet a calculated distance above it to create the exit route for the line. Castle stresses that removing or replacing these spacers would badly compromise the deepest bass, and that the floorstanders must not be used without the plinth attached. Four adjustable spikes screw into the plinth, each secured with a locknut and topped by a knob, and seats are included for hard floors such as wood or stone.

Pairing

The terminal plate has four screw binding posts for bi-wiring, joined by removable links when a single cable is used. Removing the links lets the bass section and the tweeter take separate twin core cables, which Castle says lowers intermodulation and raises headroom.

Alternatives

The Castle Knight 5 is another Knight floorstander, pairing two 150mm bass drivers with a 25mm tweeter in a 925mm tall enclosure.